BMW is due to release a slew of new turbo diesel engines in the United States throughout 2013 and 2014.

Among those in the diesel lineup is the F30 3 Series sedan diesel, due out in the first half of 2013; the F31 3 Series touring, due out in the second half of 2013; the F10 5 Series diesel, due out in the third quarter of 2013; the X5d diesel, due out at the end of 2013; the 7 Series diesel, due in the first half of 2014, and the X3d diesel, due in the first half of 2014.

According to F30Post, a 180 HP 4-cylinder engine may be assigned to 20d or 25d models while a 255 HP 6-cylinder engine may be assigned to 28d, 30d or 35d models. However, no official announcements have been made in that regard.

Wide adoption of diesel in the US would be pointless (not that I think you're implying that), and let developing countries (where tiny, cheap diesel engines are more important for productivity) and Europe balance out supply/demand to match the production ratio.

The cost benefit is a wash, CO2 (if you care) is worse, and while air pollution has vastly improved, diesel is still not nearly as clean as good gas engines.